Weird feeling in left elbow while doing skullcrushers!!

I kinda get that feeling like when I was a little kid when I lost a tooth. You know that kinda pain where it feels like something is pulling away. I've had this for 5 months now when I am doing heavy skullcrushers 135+ pounds and I just get this weird twinge feeling in only my left elbow. It went away for a while but it keeps coming back. I've also lost a little bit of strength on skullcrushers because I get less torque from that arm. Is this just tendonitis im just describing or something more serious?

In terms of the exercise: Trying taking the bar back behind your head in an extension-like manner. This reliefs a lot of stress off the elbows and places it where it's desired: Triceps. They're good for getting a nice stretch at the bottom too.

In terms of the injury: Don't push it, take time off if necessary. 1 week off voluntary is heaps better than 3-4 months forced lay-off....